Method of defoaming of sugar liquor in counter-current chip-mixers

ABSTRACT

A method of defoaming sugar juice in a countercurrent cossette mixers wherein the foam is removed from a mixer section of the cossette mixer to a let down device serving for the destruction of the foam and the juice which is freed from foam is sent back into the mixer section. The foam removal is performed by means of a juice-part-stream, the juice quantity of which is less than the raw-juice output. The foam feeding juice is distributed uniformly over the entire cross-section of the let down device and the juice part stream serving the foam removal is heated up about 5* to 10* C, so that simultaneously a partial sterilization of the sugar juice takes place in the mixer.

United States Patent [1 Schneider et al.

METHOD OF DEFOAMING OF SUGAR LIQUOR IN COUNTER-CURRENT CHIP-MIXERS v inventors: Ferdinand Schneider; Erich Reinefeld; Walter Dietzel; Wilhelm Haberich, all of Braunschweig, Germany Assignee: Braunschweigische Machinenbauanstalt, Braunschweig, Germany Filed: .Nov. 30, 1970 Appl. No.: 93,536

' Foreign Application Priority Data Dec. 2, 1969 Germany P 19 60 341.9

US. Cl 127/45, 23/270 R, 127/5, 252/361 Int. Cl Bold 11/02, C13d l/l2 Field of Search 127/2-5, 127/42, 43, 45; 252/361 FOREIGN PATENTS OR APPLICATIONS 948,500 8/1956 Germany Primary ExaminerMorris O. Wolk Assistant Examiner-Sidney Marantz AtzomeyErnest G. Montague [57] ABSTRACT A method of defoaming sugarjuice in a countercurrent cossette mixers wherein the foam is removed from a mixer section of the cossette mixer to a let down device serving for the destruction of the foam and the juice which is freed from foam is sent back into the mixer section. The foam removal is performed by means of a juice-part-stream, the juice quantity of which is less than the raw-juice output. The foam feeding juice is distributed uniformly over the entire cross-section of the let down device and the juice part stream serving the foam removal is heated up about 5 to H) C, so that simultaneously a partial sterilization of the sugar juice takes place in the mixer.

7 Claims, 1 Drawing Figure PATENIE JUL 1 11973 METHOD OF DEFOAMING F SUGAR LIQUOR IN COUNTER-CURRENT CHIP-MIXERS The present invention relates to a method of defoaming of sugar juice in countercurrent cossette mixers, in general, and to such method, in which the removal of the foam from the mixer section of cossette mixers takes place to a let-down device serving the foam destruction and the juice, which is freed from the foam, is returned into the mixer section, in particular.

During the process of the obtaining of juice in the process of the technical sugar production from beets, the occurrence of foam is extremely disturbing.

Foam is created, upon contacting the cossettes for the first time with juice and heating the same. In the present extraction towers this is brought about in additional devices disposed front of the latter (cossette mixer devices) by which the heating of the fed cossettes takes place by means of circulating hot juice and furthermore, a cossette-juice-mixture capable of being pumped is produced for the purpose of feeding into the actual extraction apparatus.

During foam formation on one hand air contributes, which air is pulled in with the reduced beets into the cossette mixer. First of all, however, during the denaturing of the beet cell structure, occurring by the heat effect, the airand gas-quantities present in the intercellular spaces of the beets, are freed. The denaturing of the beet cells is an important condition so that the saccharase from the cell structure can be transferred into the surrounding extraction liquid. The freed gas quantities are appreciable. Simultaneously, surface active content material, in particular, sapomines, move from the beet into the juice. As a consequence therefore, a tenacious foam is formed.

Foam pillows first of all prevent the desired materialand heat-exchange, as well as the counter currentguidance of the two extraction phases, beet cossettes and juice. The extraction effect is also rendered worse. Additional sugar losses by over-foaming can occur. Furthermore the important level measurements for the measuring -and control-instruments are strongly interfered with as to their exactness. Finally, also by changing level stands with stagnating foam pillows, which are subjected to a certain cooling, microbial infections are caused, which cause in turn sugar losses.

In view of these drawbacks, a foam attack is unavoidable. A removal and destruction of the foam is formidable in view of the sugar losses connected therewith. The foam treatment must take place already in the cossette mixer, in order to maintain the actual extraction apparatus foam-free to a large extent. 7

For this purpose it is known to provide high valued foam damping oils. The quantities required therefor,

are, however, extensive, particularly since a good mix ing-through and a correspondingly good exploitation of the oils in view of the construction of the known apparatus is problcmatical. The auxiliary means provided for the attack of the foam constitutes therefore an important factor of the operating costs. A further, particularly drawback of a high foam oil use are cloggings of the filtration devices and blocking of the syntetic resinion-exchangers.

Another known possibility of the foam attack resides in the fact that air conduits are provided, in which the foam can move over and at a suitable point can be precipitated by means ofjuice or also on the cold fed cossettes.

Thus a lying mixer vat is known, through which the chips can be fed through with their axis approximately parallel. The freezed air-foam mixture is thereby removed into separate foam destroyers. By using this method of operation stagnating foam pillows lead to an increased danger of infection.

In the gaining of juice lately so-called raw juices are desirable, in order to make possible the re-heating with heat at a low temperature level, in particular so-called boiling vapors and thus to obtain economical heat advantages. One such extending juice cooling can be realized only in a counter current stream. For this purpose already in cossette mixers one section is required, in which the cossettes and the juice are in a counter stream in a sealed packing. The heating of the cossettes takes place thereby slower and the foam fight becomes still more important since the matter of course, and now also the denaturation is slowed up and thereby more albumen goes into solution, which favors further the foam formation and stabilizes the foam. Furthermore, the sealed cossette packing prevents a rising of the foam.

Besides the cooling of the natural juice removal (about 110 to I20 weight a. R.) (a. R. refers to of beets) in the counter current section, the task of the cossette mixer remains to provide the remaining heating of the cossettes in a mixer section and in addition "to produce a cossette juice mixture which is capable of being pumped. In addition so-called circulation-juice is used (about 250 to 300 a.R.) with which now, however, very little heat is required to be fed (heating for only 1 to 2 C), since the counter current heat exchange suffices for the cossette heating. Now, however, again a drawback occurs which resides in the fact that the juice heating is no longer sufficient in order to bring about a disadvantageous sterilization effect.

It is one object of the present invention to provide a method of defoaming of sugar juice in counter current cossette mixers wherein the air fed with the cossettes and which is freed during the treatment can be reliably separated cossettes from the cossette-juice-mixture and can be moved off such, that neithernominal sugar losses are created, nor the above stated more closely described disturbances due to stagnating foam is to be feared and simultaneously the possibilities are created, of obtaining a sufficient and lasting sterilization effect.

It is another object of the present invention to provide a method of defoaming of sugar juice in counter current cossette mixers, wherein the 'foam removal is performed by means of a juice'part stream, the quantity ofjuice (50 to a.R.) is lower than the raw juice removal, that the foam feeding liquor in the let-down removal is equally distributed over the entire cross section and that the juice part stream serving the foam removal is heated so as to be increased in temperature for about 5 to 10 C, so that simultaneously a partial sterilization of the sugar juice takes place in the mixer device.

The removal of the foam only after subjecting it to the mixer device of the cossettes-juice-mixer has a number of advantages. Thus in the first place the rupturing of the beet cells, which is connected with the freeing of the enclosed gases, is substantially closed up at the end of the counter current section of the mixer substantially. Furthermore, the rising of the foam in the mixer section due to the low cossette filling present therein and the corresponding larger juice quantity is simplified.

The cossette mixer device is thereby to be operated such, that its total cross section is filled up. At the end of the mash section a chamber is provided, in which, a pressure release takes place which leads there to the formation and to the rising of foam, used there it is moved away immediately over the juice part stream in the let-down device.

In the let-down device the foam feeding juice is distributed byan inlet disposed at about half height uniformly over the total cross section. The cross section and the remaining time period must suffice, in order to have all released air and all the foam reaching the liquid surface.

The method in accordance with the present invention furthermore provides that the circulation juice fed into the mixer section is not heated any more rather that instead to heat the additional juice part stream provided for the foam removal. This quantity amounts to only 50 to 100% a.R. and is thus lower than the raw juice removal and much less than the circulation juice, so that for obtaining of the same heating as before in the mixer section a heating of the returned juice for about to C has to take place. This temperature increases achieves as has been ascertained above, in order to obtain in this juice part stream, a clear sterilization effect, which also effects the circuit to the entire juice. Since the stronger heated juice part stream amounts to about two third of the juice removal, the part sterilization anticipates larger infections, as microbiological experiments have disclosed. Thereby it contributes to a further elimination of sugar losses which were suffered before. The heating can be indirectly performed by steam and/or directly by feeding of tinally divided steam in the depression chamber. The

In case the'beets to be treated should release in a particular manner surface active matter into the juice, so that enormous foam quantities occur, additionally foam damping means can be added to the juice part stream. Due to the good distribution occurring thereby and the extensive effect resulting therefrom, the dose can be for example, appreciably lower relative to the previous normalrequirement and also under unfavorable conditions (beet material). With the new method, thus an accumulation and removal of the foam over an additional juice part stream and, thedestruction of the foam in a let-down device, a drastic reduction of the consumption of foam damping means and a reduction of the microbal sugar losses can be obtained by a part sterilization of the juice.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawing, in which the only Figure is a schematic showing of a juice feed.

Referring now to the drawing, a countercurrent cossette mixer l is provided which feeds thereto the raw down into a heater 8, in which it is heated for about 5 to 10 C. From there, as indicated by the arrow 9, a return of the juice part stream to the mixer section 3 takes place.

In case of the illustrated juice stream, foam damping means are fed to the juice part stream from a storage 10; thereby, this feeding must not necessarily take place after the exiting of the juice from the let-down device, rather than also it can take place in any other phase of the juice circulation.

The dashed lines 11 with the accompanying directional arrow indicates that the foam fed juice part stream can be guided also such, that it initially passes the heater 8, before it reaches the let-down device and from there again into the mixer section 3 of the countercurrent stream cossette mixer 1.

While we have disclosed several embodiments of the present invention, it is to be understood that these embodiments are given by example only and not in a limiting sense.

We claim:

1. A method of defoaming sugar juice in a countercurrent cossette mixer wherein the foam is removed from a mixer section of said cossette mixer to a letdown device in which the foam destruction occurs and the juice which is freed from the foam is returned into said mixer section, comprising the steps of removing a foam-part stream from said cossette mixer, the juice quantity of which is less than the raw juice output,

performing a mechanical. foam destruction and removal from said foam-juice part stream removed from said cossette mixer,

distributing said foam-juice part stream uniformly over the entire cross-section in said let-down device,

increasing the temperature about Sfto 10 C of the juice part of said stream, and returning the juice part of said stream with foam removed therefrom to said mixer section.

2. The method, as set forth in claim 1, wherein said step of increasing the temperature is performed at least partly by feeding of a finely divided vapor into said let-down device, causing an additional mechanical foam destruction.

3. The method, as set forth in claim I, which includes the step of adding of predetermined quantities of foam damping means to said juice-part-stream to support the foam destruction.

4. The method, as set forth in claim I, wherein said juice part of said stream flows from below in an upward direction through said cossette mixer.

5. The method, as set forth in claim I, wherein said stream is fed into said let-down device below the liquid level in said let-down device.

6. The method, as set forth in claim 1, wherein said juice in said let-down device is ventilated to the air and said juice therein is at higher pressure.

7. The method, as'set forth in claim I, further comprising the step of providing a lower-pressure in said let-down device compared to that in said cossette mixer.

18 J. i i t 

2. The method, as set forth in claim 1, wherein said step of increasing the temperature is performed at least partly by feeding of a finely divided vapor into said let-down device, causing an additional mechanical foam destruction.
 3. The method, as set forth in claim 1, which includes the step of adding of predetermined quantities of foam damping means to said juice-part-stream to support the foam destruction.
 4. The method, as set forth in claim 1, wherein said juice part of said stream flows from below in an upward direction through said cossette mixer.
 5. The method, as set forth in claim 1, wherein said stream is fed into said let-down device below the liquid level in said let-down device.
 6. The method, as set forth in claim 1, wherein said juice in said let-down device is ventilated to the air and said juice therein is at higher pressure.
 7. The method, as set forth in claim 1, further comprising the step of providing a lower-pressure in said let-down device compared to that in said cossette mixer. 